In a common design of a chassis with horizontal plugged frames, a system air duct is generally designed as a left-to-right air duct or a right-to-left air duct, so that air flows directly through surfaces of boards. This reduces system resistance and eases implementation of heat dissipation. However, this also brings some potential impacts on the heat dissipation. For example, if such air ducts are disposed in a cabinet that houses multiple devices, the air ducts of the cabinet may be in disorder. In this case, hot air may reflow and therefore affect the normal running of the devices.
A design of a chassis with horizontal plugged frames in the prior art is as shown in FIG. 1. Fans are placed on one side of the chassis, and an air inlet is set on the top or at the bottom of a board area. With this structure, air enters from the front and expels from the rear of the system for the heat dissipation of the boards in the chassis with horizontal plugged frames.
Regarding this design in the prior art, because the air inlet is set on the top or at the bottom of the board area, the air volume is unevenly distributed to the board area, which reduces efficiency of heat dissipation. In addition, because two layers of fans are disposed, the space of the chassis with horizontal plugged frames is enlarged, which reduces cost-effectiveness of heat dissipation.